It is known to oxidatively dehydrogenate alkanes, such as alkanes containing 2 to 6 carbon atoms, for example ethane or propane resulting in ethylene and propylene, respectively, in an oxidative dehydrogenation (oxydehydrogenation; ODH) process. Examples of alkane ODH processes, including catalysts and other process conditions, are for example disclosed in U.S. Pat. No. 7,091,377, WO2003064035, US20040147393, WO2010096909 and US20100256432. Mixed metal oxide catalysts containing molybdenum (Mo), vanadium (V), niobium (Nb) and optionally tellurium (Te) as the metals, can be used as such oxydehydrogenation catalysts. Such catalysts may also be used in the direct oxidation of alkenes to carboxylic acids, such as in the oxidation of alkenes containing 2 to 6 carbon atoms, for example ethylene or propylene resulting in acetic acid and acrylic acid, respectively.
It is an objective of the present invention to provide an alkane ODH and/or alkene oxidation process, wherein a mixed metal oxide catalyst containing Mo, V, Nb and optionally Te is used, wherein said alkane ODH and/or alkene oxidation process is terminated in such way that the activity and/or selectivity of said mixed metal oxide catalyst in a subsequent alkane ODH and/or alkene oxidation process is maintained.